Example usage for org.apache.commons.math.linear RealMatrix getFrobeniusNorm

Introduction

In this page you can find the example usage for org.apache.commons.math.linear RealMatrix getFrobeniusNorm.

Prototype

double getFrobeniusNorm();

Source Link

Document

Returns the <a href="http://mathworld.wolfram.com/FrobeniusNorm.html"> Frobenius norm</a> of the matrix.

Usage

From source file:net.sf.jtmt.clustering.Cluster.java

/**
 * Gets the similarity.//from  w w  w  . j a v a  2  s . c om
 *
 * @param doc the doc
 * @return the similarity
 */
public double getSimilarity(RealMatrix doc) {
    if (centroid != null) {
        double dotProduct = centroid.transpose().multiply(doc).getNorm();
        double normProduct = centroid.getFrobeniusNorm() * doc.getFrobeniusNorm();
        return dotProduct / normProduct;
    }
    return 0.0D;
}

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From source file:net.sf.jtmt.similarity.matrix.CosineSimilarity.java

@Override
public double computeSimilarity(RealMatrix sourceDoc, RealMatrix targetDoc) {
    if (sourceDoc.getRowDimension() != targetDoc.getRowDimension()
            || sourceDoc.getColumnDimension() != targetDoc.getColumnDimension()
            || sourceDoc.getColumnDimension() != 1) {
        throw new IllegalArgumentException("Matrices are not column matrices or not of the same size");
    }// www. j a  v a  2s.c o  m
    // max col sum, only 1 col, so...
    double dotProduct = dot(sourceDoc, targetDoc);
    // sqrt of sum of squares of all elements, only one col, so...
    double eucledianDist = sourceDoc.getFrobeniusNorm() * targetDoc.getFrobeniusNorm();
    return dotProduct / eucledianDist;
}

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